The Transparent Purple is certainly one of our favourites. It is a beautiful demonstrator pen with the clear barrel allowing you to see the piston-filling mechanism and you can see your ink levels clearly. You get a lot of pens for your money with this pen and the piston-action filing mechanism puts the excitement back into fountain pens. These pens do not take cartridges. The Purple Pen has a beautiful translucent purple cap and matching purple piston turning knob. It's built with impressive quality and precision so the ink is safely sealed within. The Pen has a single-turn screw cap, is quick and easy to use and has a strong chromed clip.
For the more technically minded there is a tool and silicon grease. There are also clear instructions for full disassembly although even we haven't needed to do this yet and it would only be needed for longer term cleaning and care. Proceed with care. Nice to have the tool though!